/*    $NetBSD: bsearch.c,v 1.15 2012/03/04 20:01:45 christos Exp $    */

/*
 * Copyright (c) 1990, 1993
 *    The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include "stdlib.h"

#define __UNCONST(a)    ((void *)(unsigned long)(const void *)(a))
void *bsearch(const void *key, const void *base0, size_t nmemb, size_t size,
    int (*compar)(const void *, const void *))
{
    const char *base = (const char *)base0;
    size_t lim;
    int cmp;
    const void *p;

    if (key == NULL ||base == NULL ||compar == NULL || nmemb == 0 || size == 0)
        return NULL;

    for (lim = nmemb; lim != 0; lim >>= 1) {
        p = base + (lim >> 1) * size;
        cmp = (*compar)(key, p);
        if (cmp == 0)
            return __UNCONST(p);
        if (cmp > 0) {    /* key > p: move right */
            base = (const char *)p + size;
            lim--;
        }        /* else move left */
    }
    return (NULL);
}

